+
+sub read_ld
+{
+ unless ($dataf) {
+ $dataf = IO::File->new("+>> $datafn") or die "cannot open $datafn $!";
+ $dataf->autoflush(1);
+ }
+
+ seek $dataf, 0, 0;
+ my $s = <$dataf>;
+ chomp $s;
+ dbg "read loop data: $s" if isdbg 'json';
+ $ld = $json->decode($s) if length $s;
+
+ # sort out rain stats
+ my $c;
+ if ($ld->{rain24} && ($c = @{$ld->{rain24}}) < 24*60) {
+ my $diff = 24*60 - $c;
+ unshift @{$ld->{rain24}}, 0 for 0 .. $diff;
+ }
+ my $rain;
+
+ if ($ld->{rain24}) {
+ $rain += $_ for @{$ld->{rain24}};
+ }
+
+ $ld->{rain_24} = nearest(0.1, $rain);
+ delete $ld->{hour};
+ delete $ld->{min};
+}
+
+sub write_ld
+{
+ unless ($dataf) {
+ $dataf = IO::File->new("+>> $datafn") or die "cannot open $datafn $!";
+ $dataf->autoflush(1);
+ }
+
+ seek $dataf, 0, 0;
+ truncate $dataf, 0;
+ $ld->{ts} = time;
+ my $s = $json->encode($ld);
+ dbg "write loop data: $s" if isdbg 'json';
+ print $dataf "$s\n";
+}
+
+sub cycle_loop_data_files
+{
+ $dataf->close if $dataf;
+ undef $dataf;
+
+ rename "$datafn.oooo", "$datafn.ooooo";
+ rename "$datafn.ooo", "$datafn.oooo";
+ rename "$datafn.oo", "$datafn.ooo";
+ rename "$datafn.o", "$datafn.oo";
+ copy $datafn, "$datafn.o";
+}
+
+sub grab_history
+{
+ my $lg = shift;
+ my $let = shift;
+ my $start = shift || time - 86400;
+ my $dayno = shift;
+ my @out;
+
+ if ($lg->open($dayno, 'r+')) {
+ while (my $l = $lg->read) {
+ next unless $l =~ /,"$let":/;
+ my ($t) = $l =~ /"t":(\d+)/;
+ if ($t && $t >= $start) {
+ push @out, $l;
+ }
+ }
+ $lg->close;
+ }
+ return @out;
+}